Solutions containing fluoride ions (F−) are useful in a range of chemical applications. However, aqueous solutions containing F− are problematic. For example, F− reacts rapidly with water, forming hydrogen fluoride (HF) and the complex ion HF2−. HF is generally undesirable due to its highly toxic and corrosive nature. Furthermore, HF2− is much less active, or even inactive, than F− in applications such as synthesis and electrochemistry.
To avoid these problems, the use of non-aqueous F− solutions is desirable. Notably, though, non-aqueous solutions of F− have proven difficult to prepare in concentrations high enough to be useful (e.g., greater than or equal to 0.05 M). For example, metal fluorides are highly insoluble in non-aqueous solvents, even in the presence of “solubilizing” species, such as crown ethers. Organic fluorides are typically difficult to dry to remove water contamination due to reactivity of the organic cation with F− under the drying conditions. Furthermore, in certain cases where anhydrous organic fluoride compounds are known, these compounds are poorly soluble in non-aqueous solvents.
Accordingly, there exists an ongoing need for F− solutions having improved F− concentration.